Red lead and method of making the same



Patented Dec. 13, 1927.

UNITED STATES JOHN SCEAEFFEB, 01 ST. LOUIS, AN D :1 OHN OF ST. LOUIS,

OF CINCINNATI, OHIO,

JOHN B. CBENSHAW, PICHEB LEAD COMPANY,

H. CAI-BECK, OF JOPLIN, MISSOURI, AND ILLINOIS, ASSIGNORS TO THE EAGLE- A CORPORATION OF OHIO.

BED LEAD AND METHOD OF MAKING THE SAIIE.

Jo Drawing. Application filed May 9,

the manufacture the object of our invention is to produce a red .lead havingdistinctively advantageous qualities as com- 5 pared with known red leads in that it has greater tinctorial strength, a greater E1161 ness, a higher oil absorbtion and a more orange color and also having the advantages that when converted into a red lead paint in such paint will stand up better than such paints as heretofore made when applied to smooth surfaces at a given consistency.

Our improved method consists in thor- -oughly mixing together masses of litharge, one prepared from ordinar round litharge prepared by grinding the 't arge'resultmg from subjecting melted lead to the usual furnace treatment for producing litharge, and the other a fumed litharge condensed from volatilized litharge and characterized by a very fine state of subdivision, then subjectingthe mixed mass to oxidation in a reverberatory furnace to convert the mixed lead oxides to a general composition of Pb,0,. The pigment produced is milled in g the ordinary manner and is ready for the market and is found to be distinguished from known commercial red leads in the above noted features.

Our improved pigment is in a sense a mixture of ordinary red lead and orange mineral and in qualities closely approximates those of orange mineral as heretofore generally produced though it is less costly to produce. 7

For the] best results. ground and fumed lithar we prefer to use e in approximatey eqlual quantities and t e colorand tinctoria strength can be varied by changing but we have not found it to vary the proportions above or below 40 the proportions be advantageous to more than fifteen percent the fifty percent mixture.

Our new red lead pigment can be pro- 1925, Serial No. 29,226. Renewed October 21, 1927.

duced by a thorough mixing together of red leadand orange mineral prepared in the usual ways but while the same in-kind a'pigment produced in this way is not 6 ual in qualitiyl to one produced by our descri ed new met 0d of manufacture.

We use the term litharge with reference to the ground product we employ in our new method as comprehen of furnace products and ground PhD including what in earlier practice 'was generally termed massicot,that isto say litharge formed by oxidizing lead in a furnace in which the temperature is maintained below the melting point of' litharge. This so-called massicot and litha-rge formed at higher temperature are converted into red lead by further oxidation under the same conditions as to furnace ractice.

Having now describe our invention, what we claim as new and desire to secure by Letters Patent, is:

1. The method of manufacturing red lead which consists in intimatel mixing finely round litharge prepared y subjecting a bath of melted lead to the ordinary furnace treatments and (grinding the produced litharge with fume litharge and oxidizing the mixed mass in a reverberatory furnace to a general composition of Pb,O,.

2. The method of claim 1, further characterized by mixing the two varieties of litharge in approximately equal quantities.

3. A red lead pigment consisting of an intimate mixture of red lead and orange mineral.

4. The red lead mixed red lead an orange mineral produced simultaneousl by subjecting a mixture of ground and umed litharge to oxidation in a reverberatory furnace.

JOHN A. SGHAEFFER. JOHN 'H. CALBECK. JOHN R.- CRENSHAW.

(pigments consisting of ding all varieties 

